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51.
High Catalytic Activity of Nitrogen and Sulfur Co‐Doped Nanoporous Graphene in the Hydrogen Evolution Reaction 下载免费PDF全文
Dr. Yoshikazu Ito Weitao Cong Dr. Takeshi Fujita Prof. Zheng Tang Prof. Mingwei Chen 《Angewandte Chemie (International ed. in English)》2015,54(7):2131-2136
Chemical doping has been demonstrated to be an effective way to realize new functions of graphene as metal‐free catalyst in energy‐related electrochemical reactions. Although efficient catalysis for the oxygen reduction reaction (ORR) has been achieved with doped graphene, its performance in the hydrogen evolution reaction (HER) is rather poor. In this study we report that nitrogen and sulfur co‐doping leads to high catalytic activity of nanoporous graphene in HER at low operating potential, comparable to the best Pt‐free HER catalyst, 2D MoS2. The interplay between the chemical dopants and geometric lattice defects of the nanoporous graphene plays the fundamental role in the superior HER catalysis. 相似文献
52.
Photoelectrochemical Hydrogen Production in Alkaline Solutions Using Cu2O Coated with Earth‐Abundant Hydrogen Evolution Catalysts 下载免费PDF全文
Carlos G. Morales‐Guio Laurent Liardet Dr. Matthew T. Mayer Dr. S. David Tilley Prof. Dr. Michael Grätzel Prof. Dr. Xile Hu 《Angewandte Chemie (International ed. in English)》2015,54(2):664-667
The splitting of water into hydrogen and oxygen molecules using sunlight is an attractive method for solar energy storage. Until now, photoelectrochemical hydrogen evolution is mostly studied in acidic solutions, in which the hydrogen evolution is more facile than in alkaline solutions. Herein, we report photoelectrochemical hydrogen production in alkaline solutions, which are more favorable than acidic solutions for the complementary oxygen evolution half‐reaction. We show for the first time that amorphous molybdenum sulfide is a highly active hydrogen evolution catalyst in basic medium. The amorphous molybdenum sulfide catalyst and a Ni–Mo catalyst are then deposited on surface‐protected cuprous oxide photocathodes to catalyze sunlight‐driven hydrogen production in 1 M KOH. The photocathodes give photocurrents of ?6.3 mA cm?2 at the reversible hydrogen evolution potential, the highest yet reported for a metal oxide photocathode using an earth‐abundant hydrogen evolution reaction catalyst. 相似文献
53.
One‐pot Synthesis of CdS Nanocrystals Hybridized with Single‐Layer Transition‐Metal Dichalcogenide Nanosheets for Efficient Photocatalytic Hydrogen Evolution 下载免费PDF全文
Junze Chen Dr. Xue‐Jun Wu Lisha Yin Dr. Bing Li Dr. Xun Hong Zhanxi Fan Bo Chen Prof. Can Xue Prof. Hua Zhang 《Angewandte Chemie (International ed. in English)》2015,54(4):1210-1214
Exploration of low‐cost and earth‐abundant photocatalysts for highly efficient solar photocatalytic water splitting is of great importance. Although transition‐metal dichalcogenides (TMDs) showed outstanding performance as co‐catalysts for the hydrogen evolution reaction (HER), designing TMD‐hybridized photocatalysts with abundant active sites for the HER still remains challenge. Here, a facile one‐pot wet‐chemical method is developed to prepare MS2–CdS (M=W or Mo) nanohybrids. Surprisedly, in the obtained nanohybrids, single‐layer MS2 nanosheets with lateral size of 4–10 nm selectively grow on the Cd‐rich (0001) surface of wurtzite CdS nanocrystals. These MS2–CdS nanohybrids possess a large number of edge sites in the MS2 layers, which are active sites for the HER. The photocatalytic performances of WS2–CdS and MoS2–CdS nanohybrids towards the HER under visible light irradiation (>420 nm) are about 16 and 12 times that of pure CdS, respectively. Importantly, the MS2–CdS nanohybrids showed enhanced stability after a long‐time test (16 h), and 70 % of catalytic activity still remained. 相似文献
54.
A novel, cost‐effective, and simple electrocatalyst based on a Pt‐modified glassy carbon electrode (GCE), using cetyltrimethylammonium bromide (CTAB) as a cationic surfactant, is reported. Am‐phiphilic... 相似文献
55.
A Bioinspired Molybdenum Complex as a Catalyst for the Photo‐ and Electroreduction of Protons 下载免费PDF全文
Jean‐Philippe Porcher Thibault Fogeron Dr. Maria Gomez‐Mingot Dr. Etienne Derat Lise‐Marie Chamoreau Dr. Yun Li Prof. Marc Fontecave 《Angewandte Chemie (International ed. in English)》2015,54(47):14090-14093
A molybdenum–dithiolene–oxo complex was prepared as a model of some active sites of Mo/W‐dependent enzymes. The ligand, a quinoxaline–pyran‐fused dithiolene, mimics molybdopterin present in these active sites. For the first time, this type of complex was shown to be active as a catalyst for the photoreduction of protons with excellent turnover numbers (500) and good stability in aqueous/organic media and for the electroreduction of protons in acetonitrile with remarkable rate constants (1030 s?1 at ?1.3 V versus Ag/AgCl). DFT calculations provided insight into the catalytic cycle of the reaction, suggesting that the oxo ligand plays a key role in proton exchange. These results provide a basis to optimize this new class of H2‐evolving catalysts. 相似文献
56.
Youngsoon Kim Sunghwan Shin Prof. Heon Kang 《Angewandte Chemie (International ed. in English)》2015,54(26):7626-7630
The nature of hydrated protons is an important topic in the fundamental study of electrode processes in acidic environment. For example, it is not yet clear whether hydrated protons are formed in the solution or on the electrode surface in the hydrogen evolution reaction on a Pt electrode. Using mass spectrometry and infrared spectroscopy, we show that hydrogen atoms are converted into hydrated protons directly on a Pt(111) surface coadsorbed with hydrogen and water in ultrahigh vacuum. The hydrated protons are preferentially stabilized as multiply hydrated species (H5O2+ and H7O3+) rather than as hydronium (H3O+) ions. These surface‐bound hydrated protons may play an important role in the interconversion between adsorbed hydrogen atoms and solvated protons in solution. 相似文献
57.
Dr. Michael Georg Hoesl M. Sc. Stefan Oehm Dr. Patrick Durkin Dr. Elise Darmon Dr. Lauri Peil Dr. Hans‐Rudolf Aerni Prof. Dr. Juri Rappsilber Prof. Dr. Jesse Rinehart Prof. Dr. David Leach Prof. Dr. Dieter Söll Prof. Dr. Nediljko Budisa 《Angewandte Chemie (International ed. in English)》2015,54(34):10030-10034
We have changed the amino acid set of the genetic code of Escherichia coli by evolving cultures capable of growing on the synthetic noncanonical amino acid L ‐β‐(thieno[3,2‐b]pyrrolyl)alanine ([3,2]Tpa) as a sole surrogate for the canonical amino acid L ‐tryptophan (Trp). A long‐term cultivation experiment in defined synthetic media resulted in the evolution of cells capable of surviving Trp→[3,2]Tpa substitutions in their proteomes in response to the 20 899 TGG codons of the E. coli W3110 genome. These evolved bacteria with new‐to‐nature amino acid composition showed robust growth in the complete absence of Trp. Our experimental results illustrate an approach for the evolution of synthetic cells with alternative biochemical building blocks. 相似文献
58.
Integrating NiCo Alloys with Their Oxides as Efficient Bifunctional Cathode Catalysts for Rechargeable Zinc–Air Batteries 下载免费PDF全文
Dr. Xien Liu Minjoon Park Dr. Min Gyu Kim Shiva Gupta Prof. Gang Wu Prof. Jaephil Cho 《Angewandte Chemie (International ed. in English)》2015,54(33):9654-9658
The lack of high‐efficient, low‐cost, and durable bifunctional electrocatalysts that act simultaneously for the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER) is currently one of the major obstacles to commercializing the electrical rechargeability of zinc–air batteries. A nanocomposite CoO‐NiO‐NiCo bifunctional electrocatalyst supported by nitrogen‐doped multiwall carbon nanotubes (NCNT/CoO‐NiO‐NiCo) exhibits excellent activity and stability for the ORR/OER in alkaline media. More importantly, real air cathodes made from the bifunctional NCNT/CoO‐NiO‐NiCo catalysts further demonstrated superior performance to state‐of‐the‐art Pt/C or Pt/C+IrO2 catalysts in primary and rechargeable zinc–air batteries. 相似文献
59.
Fabian Tolle Dr. Gerhard M. Brändle Daniel Matzner Prof. Dr. Günter Mayer 《Angewandte Chemie (International ed. in English)》2015,54(37):10971-10974
A novel and versatile method has been developed for modular expansion of the chemical space of nucleic acid libraries, thus enabling the generation of nucleobase‐modified aptamers with unprecedented recognition properties. Reintroduction of the modification after enzymatic replication gives broad access to many chemical modifications. This wide applicability, which is not limited to a single modification, will rapidly advance the application of in vitro selection approaches beyond what is currently feasible and enable the generation of aptamers to many targets that have so far not been addressable. 相似文献
60.
Effect of Y2O3 on microstructural characteristics and wear resistance of cobalt‐based composite coatings produced on TA15 titanium alloy surface by laser cladding 下载免费PDF全文
Donghua Lu Shasha Liu Xiaoyu Zhang Weiping Zhang 《Surface and interface analysis : SIA》2015,47(2):239-244
The effects of Y2O3 on the microstructure, phase composition of the coatings, microhardness and wear resistance of cobalt‐based composite coatings prepared by laser cladding were investigated. The TA15 titanium alloy was selected as substrate which the cobalt‐based composite powder with different content of Y2O3 was cladded on. The microstructure of the coatings was observed by scanning electron microscope (SEM) and metallurgical microscope. The phase structure of the coatings was determined by X‐ray diffraction (XRD), and the microhardness and wear resistance of the coatings were measured by hardness tester and wear testing machine. The results show that the rare earth oxide Y2O3 can refine and purify the microstructure of the coatings, reduce the porosities and cracks and improve compactness of the coatings. Moreover the addition of Y2O3 improves the microhardness of the coatings and reduces the friction coefficient, thus improving the wear property of the coatings. And the wear resistance of the coating with Y2O3 has improved about 50 times; the highest value of microhardness in the coating is HV1181.1. And 0.8 wt% content of Y2O3 in the coating is the best choice for improving the microhardness and wear resistance of the coating. It is feasible to improve the microstructure and tribological properties of laser cladding coatings by adding of Y2O3. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献